H8SLASH3028F datasheet(201/923 Pages) RENESAS

201 / 923 page

Rev. 2.00, 09/03, page 171 of 890

Example of Program Setup Procedure: Figure 6.34 shows an example of the program setup

procedure.

Set ABWCR

Set RTCOR

Set bits CKS2 to CKS0 in RTMCSR

Set DRCRB

Set DRCRA

Wait for DRAM stabilization time

DRAM can be accessed

Figure 6.34 Example of Setup Procedure when Using DRAM Interface

6.5.13

Usage Notes

Note the following points when using the DRAM refresh function.

• Refresh cycles will not be executed when the external bus released state, software standby

mode, or a bus cycle is extended by means of wait state insertion. Refreshing must therefore

be performed by other means in these cases.

• If a refresh request is generated internally while the external bus is released, the first request is

retained and a single refresh cycle will be executed after the bus-released state is cleared.

Figure 6.35 shows the bus cycle in this case.

• When a bus cycle is extended by means of wait state insertion, the first request is retained in

the same way as when the external bus has been released.

• In the event of contention with a bus request from an external bus master when a transition is

made to software standby mode, the

BACK and strobe states may be indeterminate after the

transition to software standby mode (see figure 6.36).

H8/3028F 数据表(PDF) 201 Page - Renesas Technology Corp